recommended number of listener_jobs

Brad Fitzpatrick brad at danga.com
Wed Apr 6 11:20:13 PDT 2005


Yeah, that is weird.  The mogilefsd daemon looks like:

   [ event_loop + job_manager ]

     /   /   |    |     \    \    \
  query qry qry  delete reap qry  qry


The "listener_jobs" (just an old name for the proper term: query_jobs)
shouldn't affect how many clients can connect to mogilefsd, since client
connect to the event_loop process at top, not the worker threads below.

The only effect of having too few query workers would be that if there was
a burst of traffic, they'd get queued up in the event loop for a bit.

You shouldn't be seeing connect failures.  :/


On Wed, 6 Apr 2005, Robert Rogers wrote:

> Thanks!
>
> The reason I ask about this is that while benchmarking MogileFS, I've found that when forking off requests for any more than 29 - 30 child processes the mogilefs::backend starts failing to connect and throws this error:
>
> MogileFS::Backend: couldn't connect to mogilefsd backend at /usr/lib/perl5/site_perl/5.8.5/MogileFS.pm line 91
>
> Specifically, I've got a basic fork_and_work script which forks off a number of child processes than runs thru a specified number of runs.
>
> All looks good upto children < 30. After 30 mogilefs starts rejecting requests(??).  Is this weird?
>
> Thx again.
>
> Rob
> On Wednesday, April 06, 2005, at 10:04AM, Brad Fitzpatrick <brad at danga.com> wrote:
>
> >5 or 10 would probably work.  We should make it automatic with a max cap
> >of like 50 which if it reaches means it's the database that's loaded, and
> >not the listener jobs.
> >
> >Here's our config:
> >
> ># cat /etc/mogilefs/mogilefsd.conf
> >daemonize = 1
> >db_dsn = DBI:mysql:mogilefs:host=10.0.0.48
> >db_user = mog
> >db_pass = XXXXXXXXX
> >conf_port = 7001
> >listener_jobs = 30
> >delete_jobs = 1
> >replicate_jobs = 5
> >mog_root = /mnt/mogilefs
> >reaper_jobs = 0
> >
> >
> >Though I'm not sure why we have mog_root defined... think that's old
> >historic crap that we don't use anymore now that we're using HTTP mode.
> >
> >- Brad
> >
> >
> >On Wed, 6 Apr 2005, Rob Rogers wrote:
> >
> >> Hi,
> >>
> >> Anybody have suggestions for number of listener_jobs for MogileFSD.
> >> (or for that matter a good .conf file for Mogilefsd)
> >>
> >> Thx.
> >>
> >> Rob
> >>
> >>
> >
> >
>
>


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